Source: Adam Munsterteiger of BuffStampede.comWhat we learned: The Buffaloes' offense will score more points in 2007. After finishing last in the Big 12 in total offense last season, Colorado showed vast improvement in the spring. As the Buffs enter their second year under Coach Dan Hawkins, familiarity with the system and better quarterback performance are two factors that point toward improved play.
Biggest question that remains: Who will start at defensive end? The graduation of Abraham Wright takes the Buffaloes' top pass rusher out of the picture. Alonzo Barrett and Maurice Lucas have shown glimpses of potential but are inexperienced and unproven.

Iowa State

Source: Paul Clark of CycloneReport.comWhat we learned: The Cyclones' success next season will rest largely on the development and improvement of the lines. On defense, Iowa State has three junior college players scheduled to report in the summer or fall. Each of them needs to be of starter quality, or at least be a solid backup. The offensive line will have four new starters. How well it jells is critical to quarterback Bret Meyer having a bounce-back year.
Biggest question that remains: Who are the playmakers? Wide receiver Todd Blythe is one, but there is no one else on that side of the ball who can wear the label. It's the same on defense. Linebacker Alvin Bowen is a proven playmaker, but no one else fits the bill. Junior college running back J.J. Bass needs to come in and be a playmaker, and another receiver - R.J. Sumrall or Milan Moses - needs to step up and complement Blythe. Free safety James Smith has the talent to be a star.

Kansas

Source: Jon Kirby of JayhawkSlant.comWhat we learned: The starting quarterback job remains wide open. Neither Kerry Meier nor Todd Reesing won the starting job, and the competition will continue into the fall. The offense showed a new look of getting plays from the sideline, and a variation of the no-huddle. It's also apparent the Jayhawks will use two different running backs. Jake Sharpe is a quick, cut-back runner, and Brandon McAnderson is a bruising fullback-type runner. Defensively, junior college transfer Kendrick Harper emerged as a first-team cornerback over Anthony Webb - who was a freshman All-American.
Biggest question that remains: Who will provide a pass rush from the defensive end spots? John Larson and Russell Brorsen came out of the spring as starters, but the competition is far from finished. Maxwell Onyebule moved to end and may be the most athletic player there. Jeff Wheeler has the size and range to contribute. Incoming freshman Jake Laptad has bulked up to 235 pounds and could get a chance to get on the field early.

Kansas State

Source: Tim Fitzgerald of GoPowercat.comWhat we learned: The Wildcats defense made a quick conversion from the 4-3 set it ran under Bill Snyder to a 3-4. Ian Campbell, an All-Big 12 defensive end last season, had an easy transition to outside linebacker.
Biggest question that remains: Can quarterback Josh Freeman get more consistent and cut down on turnovers? Freeman committed nine turnovers in season-closing losses to Kansas and Rutgers last season. He threw two interceptions in the spring game.

Missouri

Source: Gabe DeArmond of PowerMizzou.comWhat we learned: The Tigers offense will be as good as anticipated. Quarterback Chase Daniel threw just 12 incomplete passes in three spring scrimmages. In those scrimmages, he threw for 697 yards and eight touchdowns with just two interceptions. WR Will Franklin and TEs Martin Rucker and Chase Coffman were known quantities. Another year for Jared Perry and Danario Alexander - who earned a starting spot - and the addition of Jeremy Maclin will make Missouri's the best receiving corps in the Big 12. Running back Tony Temple rushed for 1,000 yards last season. If he does it again, Missouri has the horses to be among the nation's best offenses.
Biggest question that remains: Can the Tigers stop anyone? The return of a healthy Ziggy Hood will help heal a run defense that struggled last season. However, the major question is at cornerback now that Domonique Johnson is gone. Darnell Terrell will hold down one side, but the Tigers have no proven player at the other corner.

Nebraska

Source: Sean Callahan of HuskersIllustrated.comWhat we learned: The biggest thing we learned this spring was there shouldn't be much of a drop, if any, at quarterback for Nebraska. The Cornhuskers lost Big 12 Conference player of the year Zac Taylor, but senior transfer Sam Keller and junior Joe Ganz both had strong springs. Keller particularly look impressive, completing 10 of 13 passes for 193 yards and one in touchdown in the Red-White game.
Biggest question that remains: The obvious question that Nebraska still must answer is on the defensive line. The Huskers are replacing four starters up front, and this position continues to be a work in a progress. Another thing to follow will be the status of senior wide receiver Maurice Purify. Earlier this month, Purify was arrested for an altercation that took place in a downtown Lincoln bar. He is scheduled to appear in court later this summer for counts of assault and resisting arrest. How many games will he miss this fall because of this?

Oklahoma

Source: Carey Murdock of SoonerScoop.comWhat we learned: OU's offensive line is good enough to create running lanes for all its running backs - and not just those named Adrian Peterson. Even without 6-foot-8, 360-pound Phil Loadholt, a projected starter at left tackle, the Sooners ran more impressively than anyone could have imagined. Some of the running success could be attributed to talented backs /Allen Patrick, Chris Brown and DeMarco Murray, but the Sooners also return six players who started along the offensive line in 2006. Even though the Sooners didn't find a clear starter at quarterback, they should be able to dominate most defensive fronts on the ground.
Biggest question that remains: The easy answer is quarterback, but a deeper analysis reveals a major void at strong safety. Oklahoma has a great tradition there because of players like Roy Williams. Converted corner Reggie Smith has manned that position the last two years, but that move was viewed as a temporary solution. He moved back to cornerback this spring and no one stepped up to fill his spot. Former starting CB D.J. Wolfe took over at safety halfway through the spring. Oklahoma struggled on defense early last season because freshman Keenan Clayton didn't deliver as the starting SS. With the loss of linebackers Rufus Alexander and Zach Latimer, the Sooners cannot afford any uncertainty in the secondary.

Oklahoma State

Source: Jeff Johnson of OState.comWhat we learned: New defensive coordinator Tim Beckman is more aggressive than his predecessor, Vance Bedford. Beckman instigated several position changes this spring and challenged the Cowboys defenders to step up their games in a very personal manner.
Biggest question that remains: Can Beckman's style turn around the Oklahoma State defense? With the Cowboys' high-powered offense the defense doesn't have to be great, just solid.

Texas

Source: Geoff Ketchum of Orangebloods.comWhat we learned: The Longhorns are loaded with young talent. Although the schedule is as favorable as it could possibly be, this might be a team that's a year away from great things because of the number of first- and second-year players competing for playing time in all areas. Quarterback Colt McCoy is the star of the show, but unless some of the young defensive backs, linebackers and offensive linemen step up in a big way, a run at a national title might be asking a bit much.
Biggest question that remains: Remember when Oklahoma came into the 2007 season with major question marks along the offensive line? Well, this year it's the Longhorns' turn to face the fire. If Cedric Dockery can return in the fall from his ACL injury the offensive line will return three starters. However, the other two positions are manned by unproven players and experienced depth across the board is lacking.

Texas A&M

Source: Troy Miller of AggieYell.comWhat we learned: A&M's offense is going to be special, especially the running game. A&M has great running backs in Mike Goodson and Jorvorskie Lane, and redshirt freshman Cornell Tarrant looks solid as a backup. Fullback Chris Alexander is arguably the best in the country. They are running behind an experienced and talented offensive line.
Biggest question that remains: Will the kicking game be a liability? Kicker Matt Szymanski missed an extra point in the spring game and wasn't overly impressive during spring practices. Backup K Richie Bean doesn't have Szymanski's leg strength and isn't much more accurate. Szymanski has the talent to be an All-American candidate, but he has to turn potential into production.

Texas Tech

Source: Chris Level at RedRaiderSports.comWhat we learned: Having one quarterback is better than two. This is clearly Graham Harrell's team now, and he looked the part of a leader throughout spring. There is no ongoing quarterback race now that Chris Todd has transferred, and Harrell seems at ease and poised to lead. We also learned that Michael Crabtree will be the next great receiver at Texas Tech. He will likely push for Big 12 newcomer of the year honors. He had three catches for 112 yards and a touchdown in the Red & Black game, and that was considered an "off" day based on previous scrimmages.
Biggest question that remains: What will happen with Shannon Woods? Coach Mike Leach demoted Woods, who led the Big 12 in all-purpose yardage last season, to second string. Leach wasn't thrilled with the effort that Woods had shown in practice.

Olin Buchanan is the senior college football writer for Rivals.com. He can be reached at olin@rivals.com.